The Claim
In patients without structural heart disease, paroxysmal atrial fibrillation occurring at night is associated with a gradual increase in both high-frequency and low-frequency heart rate variability components prior to onset, followed by a significant decrease after termination, suggesting a role for increased vagal tone in the initiation and resolution of nighttime episodes.
What the research says
Supports is higher
Support is ahead, but a single strong opposing study can change this.
These are independent scores, not a percentage. Higher-grade studies count more, so a single strong opposing study can outweigh several weaker ones.
In people without structural heart disease, nighttime episodes of irregular heart rhythm are preceded by a measurable rise in both high- and low-frequency heart rate fluctuations, followed by a sharp decline after the episode ends, indicating a link to increased activity of the vagus nerve.
See the scientific wording
In patients without structural heart disease, paroxysmal atrial fibrillation occurring at night is associated with a gradual increase in both high-frequency and low-frequency heart rate variability components prior to onset, followed by a significant decrease after termination, suggesting a role for increased vagal tone in the initiation and resolution of nighttime episodes.
At night, the nerve that slows the heart becomes more active, releasing a chemical that makes heart muscle cells in the upper chambers more likely to fire abnormally. This causes the heart rhythm to become chaotic, starting an episode. When the nerve activity drops, the heart cells return to normal, and the irregular rhythm stops.
What the research says
1 studyIn people with no heart disease, this study found that before an irregular heartbeat happens at night, the nerve that slows the heart becomes more active, then calms down after the episode ends—exactly as the claim says.
Score breakdown, mechanism chain, raw evidence, ideal studies needed & 1 supporting studies
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.